correct the incorrect statements

(4) A firm's WACC will increase whenever the firm's flotation cost rate decreases, all else held constant. (5) The optimal capital structure simultaneously maximizes stock price and minimizes the WACC. (6) An increase in the market risk premium will increase a firm's WACC, all else held constant. (7) ROIC is not affected by financial leverage but ROE always increases by using financial leverage. (8) A decrease in a firm's WACC will increase the attractiveness of the firm's investment options, all else held constant. (9) Externality should focus only the negative effect on a firm's FCF. (10) Beta is the best measure the risk for an asset held in a diversified portfolio. (11) If the firm has volatile sales, the firm tends to maintain excess borrowing capacity to avoid financial distress costs. (12). If the bond is sold at part, its current yield is greater than its YTM. (13). Regardless of interest rate compounding frequency, EAR is expected to be greater than nominal interest rate. (14) All else being equal, the PV of Annuity Due is greater than PV of Annuity. (15). Unlike IRR approach, MIRR can be applied to either normal (also known conventional or non-normal (non-conventional) cash flows